This invention relates in general to electronic circuits for operating light emitting diodes (LEDs). In particular, this invention relates to a method of monitoring the operating status of one or more LEDs contained in a vehicle lamp array.
LEDs are commonly used as sources of light in a variety of applications, including vehicles (such as for headlights, taillights, signal lights, and brake lights, for example) and other devices. Typically, each of such LEDs is connected through a switching element to a source of electrical energy. When the switching element is closed, the associated LED is connected to the source of electrical energy. As a result, electrical current flows through the LED, causing it to emit light. Conversely, when the switching element is opened, the associated LED is not connected to the source of electrical energy. As a result, electrical current does not flow through the LED, causing it to not emit light. The closing and opening of the switching element is usually controlled by an electronic controller, which generates electrical control signals to the switching element. In response to such control signals, the switching element is selectively closed and opened to operate the LED in a desired manner.
Although known electronic circuits for operating LEDs have functioned satisfactorily, it is sometimes desirable to monitor the operating status of one or more of the LEDs in order to confirm that they are actually operating in the desired manner. For example, when the LEDs are contained in a vehicle lamp array, it would be desirable to alert a driver of the vehicle when one or more of the LEDs is not functioning in the manner requested, such as on/off status, level of brightness, and the like. Thus, it would be desirable to provide a method of monitoring the operating status of one or more LEDs contained in a vehicle lamp array.